The heart is a hollow muscular organ having four pumping chambers separated by four heart valves: aortic, mitral (or bicuspid), tricuspid, and pulmonary. Heart valves are comprised of a dense fibrous ring known as the annulus, and leaflets or cusps attached to the annulus.
Heart valve disease is a widespread condition in which one or more of the valves of the heart fails to function properly. In a traditional valve replacement operation, the damaged leaflets are typically excised and the annulus sculpted to receive a replacement prosthetic valve.
In tissue-type valves, a whole xenograft valve (e.g., porcine) or a plurality of xenograft leaflets (e.g., bovine pericardium) can provide fluid occluding surfaces. Synthetic leaflets have been proposed, and thus the term “flexible leaflet valve” refers to both natural and artificial “tissue-type” valves. In a typical tissue-type valve, two or more flexible leaflets are mounted within a peripheral support structure that usually includes posts or commissures extending in the outflow direction to mimic natural fibrous commissures in the native annulus. The metallic or polymeric “support frame,” sometimes called a “wireform” or “stent,” has a plurality (typically three) of large radius cusps supporting the cusp region of the flexible leaflets (e.g., either a whole xenograft valve or three separate leaflets). The ends of each pair of adjacent cusps converge somewhat asymptotically to form upstanding commissures that terminate in tips, each extending in the opposite direction as the arcuate cusps and having a relatively smaller radius. Components of the valve are usually assembled with one or more biocompatible fabrics (e.g., polyester, for example, Dacron® polyethylene terephthalate (PET)) coverings, and a fabric-covered sewing ring is provided on the inflow end of the peripheral support structure.
There is a need for a prosthetic valve that can be surgically implanted in a body channel in a more efficient procedure so as to reduce the time required on extracorporeal circulation. One solution especially for aortic valve replacement is provided by the Edwards Intuity® valve system available from Edwards Lifesciences of Irvine, Calif. Aspects of the Edwards Intuity® valve system are disclosed in U.S. Pat. No. 8,641,757 to Pintor, et al. The Edwards Intuity® valve is a hybrid of a surgical valve and a plastically-expandable stent that helps secure the valve in place in a shorter amount of time.
Despite certain advances in this area, there remains a need for a simplified prosthetic heart valve that facilitates implant and simplifies manufacturing techniques.